Problem: Luis ate 5 slices of pizza. Emily ate 2 slices. If Luis ate $\dfrac{5}{8}$ of the pizza, what fraction of the pizza was eaten?
Solution: If 5 slices represent $\dfrac{5}{8}$ of the pizza, there must have been a total of 8 slices. $\text{fraction of pizza eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${7}$ out of $8$ slices. They ate $\dfrac{7}{8}$ of the pizza.